As an ice making machine that automatically makes ice cubes, there is known a flow down type ice making machine which has a pair of ice making plates disposed vertically, facing each other and sandwiching an evaporation tube constituting a freezing system, and lets ice-making water flow down to the top surface (ice making surface) of each ice making plate, which is cooled by a coolant to be circulated into the evaporation tube, in an ice making operation to produce ice cubes, and goes to a deicing operation to separate and drop the obtained ice cubes (see, for example, Patent Document 1).
In the deicing operation of the flow down type ice making machine, hot gas is circulatively supplied to the evaporation tube and deicing water of a normal temperature is let to flow down to the back surfaces of the ice making plates to heat the ice making plates, thereby melting ice forming portions between the ice making surface and ice cubes, so that the ice cubes are dropped by the dead weight. An ice guide member which guides ice cubes, separated and dropped from the ice making plates, into an ice storage bin is disposed inclined below the ice making plates, so that deicing water falling down from the ice making plates is collected into an ice-making water tank via through holes provided in the ice guide member. Note that ice-making water which falls down from the ice making plates in the ice making operation is also collected into the ice-making water tank via the through holes in the ice guide member.    Patent Document 1: Japanese Patent Application Laid-Open No. H11-142033